Comminuting mill



Dec. 17, 1929. R. c. NEwHoUsE COMMINUTING MILL Filed Deo. 2o, 1928Patented Dec. 17, 1929 UNITED STATES PATENT OFFICE RAY C. NEWHOUSE, OFMILWAUKEE, WISCONSIN, ASSIGNOR TO ALLIS-CHALLIIERS 'MANUFACTURINGCOMPANY, OF MILWAUKEE, WISCONSIN, A CORPORATION OF DELAWARE COMMINUTINGMILL Application led December 20, 1928. Serial Nb. 327,209'.

The present invention relates in general to improvements in theconstruction and operation of rotary comminuting mills especiallyadapted for the reduction of granular material, and relates morespecifically to improved structure for supporting rotary drum mills andfor insuring effective reduction of material therein.

An object of the invention is to provide new and useful supporting andmaterial distributing structure for rotary comminuting mills, whereby arelatively simple assemblage of elements will insure highly efficient,reduction of the material. Another object of the invention is toprovide an improved drum mill wherein a tire which is employed torotatably support the mill, may also be utilized to inject material intothe interior of the drum. A further object of the invention is toprovide simple and efficient means for classifying material which hasbeen partially treated in a mill, and for subsequently returning theseparated grades to the mill for further treatment. Still another objectof theinv'ention is to provide. an improved material screening systemand mechanism for distributing the materials delivered from the screen.These and other objects and advantages of the invention will be apparentin the course of the following description.

Some of the novel features of comminuting mill and classifierconstruction disclosed butv not specifically claimed herein, form thesubject of Patent No. 1,710,666, granted April 23, 1929.

A clear conception of an embodiment of the invention and of the mode ofoperating devices constructed in accordance therewith, may be had byreferring to the' drawing accompanying and forming a part of thisspecification wherein like reference characters designate the same orsimilar parts in the several views. v

Fig. 1 is a relatively diagrammatic illustra- `tion of a multiplecompartment tube mill having the improved classifying device associatedtherewith.

Fig. 2 is a fragmentary enlarged part sectional side view of the tubemill and of the classifying device.`

Fig. 3 is an enlarged transverse section 'through the mill and throughthesupporting tire thereof.

In the drawing, the multiple compartment comminuting mill comprises ingeneral an elongated drum or shell 5 supported for rotation about asubstantially horizontal axis, by means of a tire 10and rollers 9coacting therewith at the feed end of the mill, and by means of a'trunnion 7 at the discharge end of the mill having a final dischargeopening 20 therein. The mill is segregated into successive compartments2, 3, 4, by means of screening .partitions 17, 18, and has a finaldischarge screen 19 associated therewith adjacent to the dischargeopening 20. The shell 5 is adapted to be rotated about its longitudinalaxis by means of gearing 8, and the successive compartments 2, 3, 4 areprovided with freely tumbling comminuting bodies 21, 22, 23respectively, of gradually diminishing size. The inlet end of the coarsegrinding compartment 2 is provided with a feed inlet 6 and thecompartment 2 is preferably formed of somewhat .larger diameter` thanthe other compartments 3, 4.

The shell 5 is provided with a series of peripheral discharge'openings30 at the delivery end of the coarsegrinding chamber 2 and adjacent tothe-screening partition 17. These openings in munication between thedelivery end of the coarse grinding chamber 2 and the interior of anannular screen 11 which surrounds the shell 5 and extends toward thesupporting tire 10. The screenA 11 is attachedl directly to the shell 5at one end and is secured to the shell establish comthe tire 10 at itsopposite end, being thus rotatable simultaneously with the mill.

conveyer screw 26 secured to the' interior ofv the screen 11, serves tourge material deliveed into the screen through the openings 30, towardthe tire 10, and the latter is provided with lateral openings 15 formedto conduct the screen rejects into the interior of the tire.

The interior of the tire 10 is provided with a sectional trough-shapedliner 29 and with material return plates 27 which are formed to conductthe rejects entering the tire through the openings 15, toward the shell5 during rotation thereof. The shell 5 is chamber is substantiallybalanced upon the rotary support afforded by the tire 10 and theSupporting rollers 9.

Disposed beneath the revolving screen 11,

i is a stationary trough 13, and the exterior of the screen 11 isprovided with conveyer flights 12 which during rotation of the mill,Y

cooperate with the trough 13 to urge the screened material away from thetire 10 and into a stationary receptacle 14. A pair of spiral scoops 16which are carried by the shell 5 beyond the first screening "partitions17, are formed to dip into the receptacle 14 and to elevate therelatively fine material therefrom during normal rotation of the mill.

j The inne'1 ends of the scoops 16 are provided CTI with injectors 25located within the shell 5, for returning the preliminary reducedmaterial to the intermediate comminuting chamber 3 beneath the charge ofcomminuting bodies 22 therein. The portion of the mill which is locatedin proximity to the scoops 1G and the screen 13, may be shielded by avremovable housing 2.8 which besides protecting the scoops and thescreen, prevents escape of dust when the mill is operating. The housing28 may be provided with suitable doors, not shown, for permitting accessthereto.

During normal operation of the mill, the shell 5 is being rotated aboutits longitudinal aXis'by means of the gearing 8, and the material whichis to be ground is admitted to the coarse grinding chamber 2 through theinlet opening 6. The admitted material is initially reduced in thechamber 2 by the action of the relatively large freely tumblingcomminuting bodies 21 therein., and the partially disintegrated materialis eventually delivered from the chamber 2 through the perforations inthe partition 17 and through the peripheral openings 30, to the interiorof the revolving screen 11. As the screen 1l revolves,

the convever screw 26 associated with the interior of the screen,gradually urges the material toward the tire 10 and causes the rel- Yatively fine particles to pass through the screen perforations fromwhence these particles drop into the trough 13. The relatively coarsematerial or rejects, is eventually delivered into the interior of thetire 10 through the lateral openings 15, and as the tire 10 revolves,these rejects are urged inwardly toward the shell 5 by the plates 27 andare returned to the medial portion' of the coarse grinding chamber 2beneath the charge 'of comminuting bodies and material therein, by theinjectors 24 as shown in Fig. 3. The relatively fine material depositedin the trough 13, is urged toward the stationary receptacle 14 by meansof the conveyor flights 12 secured to the exterior of the screen 11, andsubstantially fills the receptacle 14 as shown in Fig. 2. The revolvingscoops 16 which dip into the stationary receptacle 14 remove therelatively fine material therefrom and inject the said material to theinlet end of the intermediate comminuting chamber 3 beneath the chargeof comminuting bodies 22 therein, through the vinjectors 25. In theintermediate chamber 3, the admitted material is further reduced by thefreely tumbling communiting bodies 22 as it advances toward the secondscreening partition 18. After having been further reduced in theintermediate comminuting chamber 3, the material is eventually deliveredthrough the partition 18 to the inlet end of the fine grinding chamber4. In the chamber 4 the material is finally reduced by the relativelysmall freely tumbling comminuting bodies23, and the final product iseventually delivered past the discharge screen 19 and from the millthrough the discharge opening 20.

From the foregoing description it will be apparent that the materialadmitted to the mill is treated in the successive chambers 2, 3, 4 togradually reduce the same to a ne powder. f Each .of the severalchambers is provided with freely tumbling comminuting bodies which arebest adapted to effectively f reduce the material treated inl thatchamber. In view of the fact that the relatively large comminutingbodies 21 are effective initial reducers when acting with considerableimpact, it is desirable to make the coarse grinding chamber 2 ofrelatively large diameter as compared to the fine grinding chambers, soas to increase the peripheral velocity at the chamber 2 and therebyincrease the cascading action of the charge in this chamber. As thecharge within the initial or coarse grinding chamber 2 is relativelyheavy, it has been found desirable to support the inlet end of the millon a tire 10 instead of on a trunnion such as is customarily used at thedischarge end of the mill. By placing the tire 10 at the medial portionof the coarse grinding chamber 2, the charge within this chamber issubstantially balanced upon the tire.

With the construction of vthe present invention, the tire 10 may also beutilized for the purpose of returning the screen rejects to the medialportion of the coarse grinding chamber 2, it being most desirable toadmit these rejects at this portion of the chamber 2. The interior ofthe tire 10 may be provided with liners 29 adapted to efectively resistthewear, and the openings 15 being of relatively small size do notmaterially impair the strength of the tire. The conveyers 26,'12 serveto effectively distribute thematerial and to keep the screen 11 fromclogging. These conveyers being attached to the screen l1 functionautomatically during operation of the mill, and the classifying screen11 serves vto enhance the capacity of the mill by permitting rapiddelivery of the sufficientl reduced material from the coarse grindingchamber 2. Such material if ypermitted to remain Within the chamber- 2,undesirably cushions the impact action of the bodies 2l, and can be moreeffectively treated with smaller comminuting bodies such as employed inthe intermediate chamber 3. The scoops 16 likewise serve toautomatically inject the material delivered from the coarse grindingchamber 2 to the intermediate chamber 3, during-operation of the mill,and the entire assemblage obviously -provides a relatively simple andhighly efficient structure for effecting reduction of the material.

It should-be understood that it is not desired to limit the invention tothe exact details of construction and operation herein shown anddescribed, for various modifications Within the scope of the claims mayoc cur to persons skilled in the art.

It is claimed and desired to secure ters Patent:

l. In combination, a rotary shell forming acomminuting chamber, a tirerotatably supporting said shell and having a passage communicable withsaid chamber, means for classifying material delivered from saidchamber, and means for returning material from said classifying means tosaid chamber through said tire passage.

2. In combination, a rotary shell forming a comminuting chamber, aplurality of freely tumbling comminuting bodies Within said chamber, atire surrounding said chamber and rotatably supporting said shell, saidtire having an internal passage communicable with said chamber, meansfor classifying material delivered from said chamber, and means forreturning material from said classifying means to said chamber beneathsaid bodies and through said tire passage.

3. In combination, a rotary shell forming a comminuting chamber, a tirerotatably supporting said shell and having a passage comntunicable withsaid chamber, a screen for classifying material delivered` from said byLetlchamber. and means, for returning rejects from said screen vto saidchamber through said tire passage.

In combination, a rotary shell forming a cemminutin chamber, a tirerotatablysupporting said s vfell and ha: ng a passage communicable withsaid chamber, anannular screen surrounding said chamber and rotatablewith said shell for classifying material delivered from said chamber,and means for returning rejects from within said screen to said chamberthrough said tire passage.

5. In combination, a rotary shell forming a comminuting chamber, aplurality of freely tumbling comminuting bodies Within said chamber, atire surrounding said chamber and rotatably supporting said shell, saidtire having an internal passage communicable with said chamber, anannular screen also surrounding said chamber and rotatable with saidshell for classifying material delivered from said chamber, and meansfor returning rejects from Within said screen to said chamber beneathsaid bodies and through said tire passage.

6. In combination, a rotary shell forming a comminuting chamber, atrunnion of less diameter than said shell rotatably supporting one endthereof,'a tire of greater diameter than said shell surrounding theopposite end thereof and rotatably supporting the same, said tire havinga'passage communicable with said chamber, means for classifying materialdelivered-from said shell intermediatc said ends, and means forreturning material from said classifying means to saidn chamber through'said tire passage.

7. In combination, a rotary shell forming a comminuting chamber, meansincluding a vtire for rotatably supporting said shell at its oppositeends, said tire having a passage communicable With said chamber, meansfor classifying material delivered from said shell intermediate saidends, means for returning material from said classifying means to saidchamber through said tire passage, and other means for returning othermaterial from said classifying means to the interior of said shell.

8. In combination, a rotary shell, means dividing said shell intosuccessive chambers, a tire surrounding one of said chambers androtatably supporting said shell, said tire having a passage communicableWith said chamber, means for classifying material delivered from one ofsaid chambers, means for returning material from lsaid classifying meansto one of said chambers through said tire passage, and ,other means forreturning material from said classifying means to another of saidchambers.

9. In combination, a rotary shell forming a comminuting chamber, aftirerotatably supporting said shell, and having a passage communicable withsaid chamber, an annular screen surrounding said chamber and rotatableWith said shell for classifying material delivered from said chamber,the interior of said screen communicating directly with said passage, aconveyer Within saidscreen for urging material therealong and into saidtire 'chamberand being communicable With said adjacent to said tire andcommunicating directly with said chamber, means for urging materialalong said screen and into said tire passage, means for returning saidmaterial from saidtire to said chamber, and means for returning materialwhich passes through said screen to the interior of said millindependently of said tire,

11. In combination, a rotary shell forming a comminuting chamber, a tirerotatably supportinfr said shell and having a passage com` municablewith said chamber, an annular screen surrounding said chamber adjacentto said tire for classifying material delivered from said chamber, saidscreen being rotatable with said shell and communicating directly withsaid chamber and with said tire passage, means for urging material alongsaid screen and into said tire passage, means `for returning saidmaterial from said tire passage to said chamber, a stationary troughdisposed in proximity to said screen, and means for returning materialfrom said said chamber, and means for deliveringmaterial to said tirepassage whereby said Inal terial is introduced'into said shell throughsaid tire passage.

15. In combination, a rotary drum forming a conuninuting chamber, ascreen rotatable With said drum and formed to 'receive y material from amedial portion of said chamber, a stationary receptacle adapted toreceive material passing through said screen, means for deliveringmaterial from said receptacle RAY C. NEWHOUSE.

trough to the interior of'said mill independl ently of said tire.

12. In combination, a rotary shell forming `a comminuting chamber, atire rotatably supporting said shell and having a passage communicablewith said chamber, an annular screen surrounding said chamber adjacent.to said tire for classifying material delivered from said chamber, saidscreen being rotatable With said shell and communicating directly withsaid chamber and with said tire p passage, means for urging materialalong said screen and into said tire passage, means for returning saidmaterial from said tire passage to said chamber, a stationary troughdisposed 1n proxiimty to \.-sa1d screen, means associated with saidscreen for urging material along said trough, a stationary receptacleformed to receive material from said trough, and a plurality of scoopsoperable by said shell for returning material from said 'receptacle tothe interior of the mill independently of said tire.

13. In combination, a rotary shell forming a comniinnting chamber, atire rotatably sup'- porting said shell and having a passagecommunicable with said chamber, and means for delivering material tosaid tire passage whereby said material is introduced into said shellthrough said tire passage.

14. .In combination, a rotary shellV forming a comminutingchamber, ahollowtire rotatably supporting a medial portion of said shell andhaving. a passage communicable with figo

